If pressure sensors, pressure transmitters and other field equipment are used near flammable gases or dust, they might be subject to marking in accordance with the ATEX product guideline 94/9/EC. Crush requires the type label of the sensor to include the ATEX marking, so usually that is labelled directly onto the sensor during production.
Next to the Notified Body and the approval number, the marking of pressure sensors also includes important information for the user. For instance, an ?X? following the approval number indicates that special conditions must be observed with all the device. These are either given in the approval document and in the corresponding manual. Above all, marking according to ATEX gives home elevators the possible regions of application and the sort of protection used for the pressure sensor:
Explosion group:
I Mining industry, II other areas of use Device class:
Used in zone 0/20 in the vicinity of von flammable gases (1G), dust (1D)
Used in zone 1/21 near flammable gases (2G), dust (2D)
Used in zone 2/22 near flammable gases (3G), dust (3D)
However, additionally, there are devices where only certain parts may be installed in other zones, for instance, a pressure sensor marked 1/2G could be installed in a tank with flammable content. The electronic the main transmitter is located externally of the tank, and therefore in zone 1.
Examples for forms of protection:
i intrinsic safety (Limitation of electrical ignition energy by limiting current and voltage)
ia for Zone 0 or Zone 20 (for Zone 20 also iaD)
ib for Zone 1 or Zone 21 (for Zone 21 also ibD)
ic for Zone 2 d
flameproof / explosion proof enclosure, ideal for zone 1/21 and 2/22 n
non-incendive, suitable for zone 2/22 m
encapsulation ideal for zone 1/21 and 2/22 Gas group and temperature class: i.e. IIC T1 for hydrogen
Note:
Further information on the subject of hydrogen can be found on the WIKA website. For those who have any further questions, your contact will gladly assist you to.